Voronezhskiy gosudarstvennyy universitet
A comparative analysis of methods for determining the radius of the nuclear neck radius (𝑟neck) at the point of its rupture during actinide fission is presented. Classical approaches based on the liquid drop model, modern methods of the density functional theory with time dependence and the Born-Oppenheimer approximation are considered. An alternative method based on the concept of "cold" fission with an analysis of the spin distributions of fragments is proposed. A quantitative relationship between the neck radius and the spins of fragments through transverse bending and wriggling oscillations is established. It is shown that for 235U, 238U and 252Cf the neck radius is 1.5 – 2.2 fm, which is consistent with various theoretical approaches.
nuclear fission, nucleus neck radius, spin distribution, cold fission, fragment deformation
1. Bohr, N. The Mechanism of Nuclear Fission / N. Bohr, J.A. Wheeler // Physical Review. – 1939. – Vol. 56, No. 5. – P. 426-450.
2. Bohr, A. Nuclear Structure / A. Bohr, B.R. Mottelson. – New York: Benjamin, 1975. – Vol. 2: Nuclear Deformations. – 740 p.
3. Wagemans, C. The Nuclear Fission Process / C. Wagemans. – Boca Raton: CRC Press, 1991. – 608 p.
4. Rupture of the neck in nuclear fission / K.T.R. Davies, R.A. Managan, J.R. Nix, A.J. Sierk // Physical Review C. – 1977. – Vol. 16, No. 5. – P. 1890-1901.
5. Bulgac, A. Time-dependent density functional theory and the real-time dynamics of Fermi superfluids / A. Bulgac // Annual Review of Nuclear and Particle Science. – 2013. – Vol. 63, No. 1. – P. 97-121. – DOI:https://doi.org/10.1146/annurev-nucl-102212-170631.
6. Fission fragment intrinsic spins and their correlations / A. Bulgac [et al.] // Physical Review Letters. – 2021. – Vol. 126, No. 14. – P. 142502. – DOI:https://doi.org/10.1103/PhysRevLett.126.142502.
7. Bulgac, A. Nuclear fission dynamics with time-dependent density functional theory / A. Bulgac, S. Jin, I. Stetcu // Physical Review C. – 2019. – Vol. 100, No. 3. – P. 034612. – DOI:https://doi.org/10.1103/PhysRevC.100.034612.
8. Pomorski, K. Mass distribution of fission fragments within the Born-Oppenheimer approximation / K. Pomorski, F.A. Ivanyuk, B. Nerlo-Pomorska // The European Physical Journal A. – 2017. – Vol. 53, No. 3. – P. 59. – DOI:https://doi.org/10.1140/epja/i2017-12250-5.
9. Fission fragment mass yields of Th to Rf even-even nuclei / Pomorski K. [et al.] // Chinese Physics C. – 2021. – Vol. 45, No. 5. – P. 054109. – DOI:https://doi.org/10.1088/1674-1137/abec69.
10. Spin measurements in fission / J. Wilson, D. Thisse, M. Lebois [et al.] // Nature. — 2021. — Vol. 590, No. 7847. — P. 566–570.
11. Vogt, R. Angular momentum effects in fission / R. Vogt, J. Randrup // Physical Review C. – 2021. – Vol. 103. – P. 014610.
12. Spinovoe raspredelenie fragmentov dvoynogo deleniya atomnyh yader s uchetom wriggling- i bending-kolebaniy / S.G. Kadmenskiy, D.E. Lyubashevskiy, D.A. Stepanov, A.A. Pisklyukov // Yadernaya fizika. – 2024. – T. 87, № 3. – S. 288-294. – DOI:https://doi.org/10.31857/S0044002724030182.
13. Role of bending mode in generation of angular momentum of fission fragments / Shneidman T.M. [et al.] // Physical Review C. – 2002. – Vol. 65, No. 6. – P. 064302. – DOI:https://doi.org/10.1103/PhysRevC.65.064302.
14. Nuclear structure with the dinuclear model / Adamian G.G. [et al.] // Physics of Atomic Nuclei. – 2004. – Vol. 67. – P. 1701-1708.
